Moisture resistant bristles for brushes and the like



Patented Apr. 10, 1934 UNITED STATES MOISTURE RESISTANT BRISTLES FOR BRUSHES THE LIKE w mite Western Teller, Chicago, 111-, Bottle Manufacturing Col,

'assignor to Chicago,

Ill., a. corporation of Illinois No Drawing.

Application December 12, 1931' Serial No. 580,133

8 Claims. (Cl. 15-167) This invention relates to improved bristles for brushes and a method for their preparation.

The better grades of bristles are'obtained from wild boars. For use in brushes the hair bulb or root is removed anda portion of the hair immediately above the root is cut off for use as a bristle. This portion is generally solid, but the outer end of the hair is hollow and undesirable for use as a bristle in the better class of brushes since the hollow bristles tend to fray and do not stand up. Both grades of bristles, when wet, absorb considerable percentagesof water and become soft and soggy, and therefore are somewhat objectionable for use in tooth brushes and hair brushes. Because of the prevalent use of soaps in tooth pastes, the bristles of tooth brushes are subjected, in use, to a very drastic wetting action that quickly softens them and renders them less effective in cleansing the teeth.

This invention comprises a method whereby bristles may be made more water-resistant so that they will be better adapted for tooth brushes and like uses.

It is, therefore, an object of this invention to provide a water-resistant bristle for tooth brushes and the like.

It is a further object of this invention to provide a process by which water-resistant bristles may be produced.

Other and further'objects of this invention will become apparent from the following specification, and the accompanying claims.- I

I have found that by dipping the bristles, first into a solution of a heavy metal salt and then into a solution containing a water soluble soap of a fatty acid, I can produce a bristle which is high- 1y water-resistant and the sheen or lustre of which is not impaired. I prefer to dip the bristles into a solution of a heavy metal salt, for instance an aluminum salt, first and into the soap solution afterward because, if the salt is used last, the lustre or sheen of the bristle will be largely destroyed.

For purposes of illustration, I give an example of a preferred form of my process. The bristles to be treated are bleached by any suitable method and then soaked in a solution which may be from 1 to 3% of a soluble aluminum salt. I prefer aluminum acetate because of its cheapness. After soaking the bristles in this solution until thoroughly impregnated, they are transferred to a solution of any suitable soap. I prefer to use about a 4% solution'of a castile soap dissolved in water.

It is to be understood that other proportions ,ever, that the metal be one than 1 to 3% of aluminum salt will be operative in my process since there is nothing critical about the percentage used. Other salts than those of aluminum are satisfactory for mypurpose. In fact, any soluble salt of a metal which will form an insoluble soap may be used. I prefer, howwhich forms a white, insoluble soap, such as, for example, those common, non-poisonous metals occurring in the second, third and fourth groups in Mendelejeffs B5 Periodic Table. I can also use metals which produce a colored, insoluble soap, but this will color the bristles and Iprefer that they be as white as possible.

The impregnation of the bristles with an insoluble soap may be accelerated and the water repellant qualities of the bristles improved by an electrolytic method, according to which the bristles are first loosely matted, the mat of bristles wetted with a; saponaceous compound andthen passed through roller electrodes, while spraying the matted bristles with an aqueous solution of heavy metal salt during their passage through the roller electrodes. In this way an insoluble, water repellant precipitate is formed by the'uniting of the reacting constituents simultaneously with the action of the electric current on the matted bristles.

It is possible to treat the bristles in one operation. I accomplish this by impregnating them with a solution of any heavy metal salt of a fatty acid dissolved in naphtha or other suitable organic solvent, and allowing the solvent to evaporate.

Another modification of my invention which produces a water resistant bristle comprises dip-' ping the bristles into asolution of Chinese, Japan, beeswax or other suitable wax dissolved in xylene or other suitable organic-solvent, and allowing the solvent to evaporate. This method greatly improves the quality of the bristle. Working tests have shown that brushes having bristles treated in this manner stand up much better than brushes having bristles not so treated. For example, bristles treated with Chinese wax 'and xylene stood up under a test consisting of 50,000 strokes under water while untreated bristles did not. However, I prefer the precipitation of an insoluble soap within the bristle since this produces a better product than impregnation with the Chinese wax.

It will be understood that the insoluble metal soaps and waxes used in accordance with my invention for waterproofing bristles prevent the absorption of water by the bristles largely because of 0 ibility or rigidity originally possessed by the bris- In other words, soft bristles will still be soft tles. after being subjected to the waterproofing treatment herein described. This is important inas-' much as soft or medium hard bristles find widespread use in tooth brushes and it is desirable to waterproof these types of bristles as well as the harder types.

It is also possible to impart tothe bristles a water repellant effect by impregnating the bristles with a fat, such as stearin or palmitin, but this method is not to be preferred since the soaps in tooth-pastes have a saponifying action toward such fats that eventually causes the destruction of the water repellant property of the fat impregnated bristles.

I have found that my process makes possible the use of those portions of the original fiber which are hollow. When hollow fibers are treated according to my process, their quality is so improved that they may be used for many purposes to which they would not be otherwise adapted.

Thus it will material improvement in the art of producing bristles for brushes and have produced a bristle of greatly improved quality both in its water-resisting property and its durability.

I am aware that numerous details of my process may be varied through a wide range without said bristles less be seen that I have made a very departing from the principles of my invention, and I therefore do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

1. A tooth brush having bristles treated with a water repellant substance adapted to render said bristles less water absorptive than before treatment.

2. A tooth brush having bristles treated with a "water repellant insoluble soap adapted to render said bristles less I treatment.

water absorptive than before 3. A tooth brush having bristles treated with a water repellant waxy substance adapted to render water absorptive than before treatment.

4. A tooth brush having bristles impregnated with an aluminum soap of a fatty acid.

5. A tooth brush having bristles, the interior portions of which contain an insoluble soap, whereby the ability of said bristles to absorb water is reduced.

6. A tooth brush having bristles, the hollow portions of which contain a wax, whereby the ability of said bristles to absorb water is reduced.

7. A brush having animal bristles coated and impregnated with a water repellant soap to render said bristles more resistant to the absorption of water without materially altering their original degree of flexibility.

8. A brush composed of animal bristles having hollow portions therein, the cavities thereof being filled with a waxy substance that imparts water resistance to said bristles without materially altering their original degree of flexibility.

W KEDZIE TELLER. 

